Tissue-Specific Lipid Profiles and Valorization Potential of Oils from Processing By-Products of the Invasive Blackchin Tilapia (Sarotherodon melanotheron).

The global expansion of invasive aquatic species poses several ecological and economic challenges while generating underutilized biomass. Blackchin tilapia (Sarotherodon melanotheron) is an invasive fish species in Thailand, but its processing by-products remain poorly characterized as sources of tissue-specific lipids. This study evaluated the oil yield, fatty acid composition, nutritional quality indices (NQIs), lipid oxidation status, and volatile compound profiles of the oils recovered from the head, viscera, roe, and mixed processing by-products. The crude oils were characterized by gas chromatography-flame ionization detection and headspace gas chromatography-electronic nose analysis. The head produced the highest oil yield (17.5% dry-weight basis), whereas the roe oil showed relatively more favorable nutritional characteristics among the tissue-derived oils examined, with the highest relative polyunsaturated fatty acid level (14.8% of total fatty acids); the presence of eicosapentaenoic acid (EPA; 3.0% of total fatty acids) and docosahexaenoic acid (DHA; 7.4% of total fatty acids); a polyunsaturated fatty acid/saturated fatty acid ratio of 0.288; and a fish lipid quality index (10.47). The crude oils differed in their lipid oxidation status, with head oil showing the highest and roe oil the lowest oxidation indices. Volatile compound profiling resulted in the identification of 22 major compounds and revealed distinct tissue-dependent patterns, with 1-propanethiol as the predominant volatile compound in the roe oil (84.2%) and 2-hexanol as a major volatile compound in the head oil (23.6%). These findings demonstrate the distinct valorization potential of blackchin tilapia by-products and provide a basis for tissue-specific selection and further processing of invasive fish-derived oils.